March 6, 2014
The ancient reptile Dimetrodon exhibited a variety of different tooth shapes, probably due to evolutionary pressure from competitors who fed on similar prey.
March 3, 2014
New research combines the traditional method of studying fossilized pollen with new DNA techniques to look at arctic plants 50,000 years ago.
March 2, 2014
Humans in all societies form and participate in cooperative alliances. Common enemies are not necessary to erase important social boundaries; peaceful cooperation can have the same effect.
February 26, 2014
Scientists say aggression-causing genes appeared early in animal evolution and have kept their roles for millions of years, even though animal aggression today varies widely.